1. Field of the Invention
This invention relates to novel polyester compositions, sizing compositions, and processes for sizing yarn utilizing said compositions as binders or coatings for fibrous articles such as spun or continuous filament textile yarn.
2. Description of the Prior Art
Prior to the weaving operation, continuous fialment synthetic fiber warp yarn is usually given a twist of about 5 to 15 turns per inch and treated with a sizing composition which binds the filaments of the yarn together so as to strengthen the yarn by rendering it more resistant to abrasive forces to which it is exposed during the subsequent weaving operation. Sizing materials must confer on the yarn resistance to abrasion as well as provide additional properties such as elasticity, flexibility, and low tack. In addition, the size must be easily removed subsequent to the waving operation in order to return the yarn to its unsized state in which dying treatments are often performed.
Textile sizing compositions are commonly applied to textile fibers from water dispersions. In U.S. Pat. No. 3,981,836, it is disclosed that a suitable size can be prepared by copolymerizing a styrene-maleic anhydride copolymer in the presence of an unsaturated dicarboxylic acid and a monohydric or polyhydric alcohol. The composition can be converted to a water-dispersible polymer by neutralizing some of the carboxyl groups of the resulting copolymer with an alkali metal hydroxide or ammonium hydroxide.
It is also known from U.S. Pat. No. 4,002,700 to prepare compositions useful as adhesives, coatings, printing inks and binders by reacting a dibasic acid component containing an .alpha., .beta.-ethylenically unsaturated dibasic acid with a glycol to form an unsaturated polyester which is reacted with a base to neutralize unreacted carboxyl groups and render the polyester water soluble. The water-soluble polyester can be cured utilizing a monovinyl compound subsequent to application to a substrate.